Portal 2 Free “Peer Review” DLC Released, Sale on Steam

Portal 2’s Co-Op mode just got a little larger with the release of Valve’s free “Peer Review” DLC, which adds more to the story of Atlas, P-Body, and everyone’s favorite passive-aggressive homicidal AI, GLaDOS.

In addition, the DLC pack adds challenge maps to both single player and co-op, as well as leaderboards so you can show off how great you are. Valve also decided to put Portal 2 on sale on Steam for just $14.99 until October 6th to celebrate, so get it if you don’t have it already.